The perk for OnStar-equipped model year 2014 Chevrolet, Buick, GMC and Cadillac vehicles will continue for the full five years "even if the owner declines to pay for other OnStar service," Phil Abram, chief infotainment officer for GM, said in an interview.

Abram described the move as an attempt to appeal to the desires of GM customers, noting that 72% of those polled on the subject said that the RemoteLink Mobile App "positively influences their decision to purchase GM vehicles. They like it and they use it."

The same app allows a driver to remotely turn on the engine to warm the car in cold climates or to cool it if a traveler is returning to a car that has been sitting in the heat of Southern California in August, for example.

Experts said it was another example of the growing interface between smartphone apps and the automotive industry.

"Wherever you go, during every spare minute people are consulting their phones," said Jack Nerad, executive editorial director and market analyst for Kelley Blue Book. "This gives them something else they can do with it."

Nerad added: "This one really answers a need. You are sitting at the dining table with your lovely wife and kids and can't remember if you locked your car. The fact that you can use this app and not have to walk back to the parking garage is seen as a boon to mankind."

Nerad said that future automotive purchases may be based more on which brand offers the best integration of things like apps and smartphone technology.

"These kinds of conveniences are more important to everyday driver satisfaction than how fast the car will go or how well it will corner," Nerad said.

GM's Abram said that 36 model year 2014 GM vehicles are compatible with the RemoteLink mobile app. The app works on Apple, Android and Blackberry phones.

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